Proteinuria selectivity index based upon alpha 2-macroglobulin or IgM is superior to the IgG based index in differentiating glomerular diseases. Technical note
BACKGROUND: The proteinuria selectivity index (SI) may be used to describe changes of the glomerular permeability for macromolecules in glomerular diseases. Proteins the size of alpha 2-macroglobulin (alpha 2 M) or IgM cannot normally pass the glomerular barrier, whereas IgG can pass through the large pores of glomerular basement membrane. Comparison of the clearance of the three high-molecular-we